Including an animatied plot in animation
One way to do this is using the Blender video editor. 
You create the animation and render it to a sequence of images. Then create you animated graph and save it as a sequence of images.
In the video editor, you add the animation as an image sequence in one channel. Then in the next channel add the graphs as an image sequence. Use the editor settings for the graph to position and scale the graph.
When the video is rendered, the graph will be overlaid on the animation.